The present invention is directed to a method for increasing the percentage of mammalian offspring of either sex by contacting a sperm sample with an antibody specific for one sex, the antibody being bound to a magnetic bead of a diameter which permits separation of spermatozoa having sufficient motility to permit successful insemination and fertility.
Farmers and other animal husbandry persons have long recognized the desirability of enhancing the probability of offspring of a selected sex. Methods have been proposed in the past for increasing the percentage of X-sperm cells or Y-sperm cells to thereby achieve a greater chance of achieving male or female offspring, respectively. Examples of prior research are reviewed, for example, in Garner, D. L. et al., "An Overview of Separation of X- and Y-Spermatozoa," Proceedings of the Tenth Technical Conference on Artificial Insemination and Reproduction (National Association of Animal Breeders), pp. 87-92 (1984) and Pinkel, D. et al., "Flow Cytometric Determination of the Proportions of X- and Y-Chromosome Bearing Sperm In Samples of Purportedly Separated Bull Sperm," J. Animal Scien., 60, pp. 1303-1307 (1985).
Previous methods have included, for example, methods based upon density sedimentation (see, for example, Brandriff, B. F. et al. "Sex Chromosome Patios Determined by Karyotypic Analysis in Albumin-Isolated Human Sperm," Fertil. Steril., 46, pp. 678-685 (1986))
U.S. Pat. No. 3,687,806 to Van Den Bovenkamp discloses an immunological method for controlling the sex of mammalian offspring by use of antibodies which react with either t he X- or Y-chromosomes and utilizing an agglutination step to separate bound antibodies from unaffected antibodies.
U.S. Pat. No. 4,191,749 to Bryant discloses a method for increasing the percentage of mammalian offspring of either sex by use of a male-specific antibody coupled to a solid-phase immunoabsorbant muateria to selectively bind male-determining spermatozoa, while the female-determining spermatozoa remain unbound in a supernatant.
U.S. Pat. No. 5,021,244 to Spaulding discloses a method for sorting living cells based upon DNA content, particularly sperm populations to produce subpopulations enriched in X- or Y-sperm by means of sex-associated membrane proteins and antibodies specific for such proteins.
However, these methods often result in insufficient separation of X- and Y-sperm and often damage the sperm, thereby reducing its motility and fertility success rate.